1. How to remove large tables of data to improve performance?
delete from tablename where condition, the condition may be the index will be faster, but almost line by line how to delete it up
Instead truncate table, large tables transformation of partition table (this is based on the time you are not very good direct trancate full table) truncate better based on partition
2. The main table inner join large data center performance data limit tables and Exist?
Two tables have been carried out then the third inner table, you are
select t1.*,t2.* from tabel1 t1,tabel2 t2,table3 t3 ...
still is
select t1,*,t2* from table1 t1,table2 t2
where exist table3 ...
As used herein, mainly because Select Exist not take data from T3, just to limit the scope, does not need to Inner,
Then the ratio of the difference of the way with the inner exist in operation Where?
(I did not write the whole sentence, just record some thoughts comparison)